noun: 1. A blanket carried by a child to reduce anxiety. 2. InformalSomething that dispels anxiety.

For anxiety, as we have come to use it to describe our characteristic state of mind, can be contrasted with the active fear of hunger, loss, violence and death. Anxiety is the appropriate emotion when the immediate personal terror—of a volcano, an arrow, the sorcerer’s spell, a stab in the back and other calamities, all directed against one’s self—disappears.Margaret Mead (1901–1978), U.S. anthropologist. “One Vote for This Age of Anxiety,” sect. VI, New York Times (May 20, 1956).

...when the immediate personal terror......disappears. I would say that this is a security blanket, not a wet blanket, for us when we question our mortality...and remember it...Memento Mori.